Copolymer Fiber Composition for Dyeable Flame-Resistant Apparel

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Solution Overview

Problem

Existing fibers made from diaminodiphenyl sulfone monomers are expensive and not widely available, limiting the development of high-temperature stable, dyeable, and flame-resistant polymers.

Innovation Solution

A copolymer fiber is developed using 3,3'diaminodiphenyl sulfone as at least 25 mole percent of the amine monomers, combined with an acid monomer like terephthaloyl chloride, to create a fiber with high sulfone groups for dyeability and solubility in organic solvents, while maintaining para-oriented structure for high temperature stability and flame resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If diaminodiphenyl sulfone monomers are used to make fibers, then the fiber has high sulfone groups for dyeability and solubility, but the fiber becomes expensive and the monomers are not widely available

Engineering Contradiction:
Improvedyeability and solubilityVSAvoidcost and availability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the chemical composition parameters by using 3,3'-diaminodiphenyl sulfone at least 25 mole percent of total amine monomers combined with other aromatic diamines, creating a copolymer that maintains sufficient sulfone groups for dyeability while reducing dependency on expensive pure diaminodiphenyl sulfone monomers

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite copolymer system combining 3,3'-diaminodiphenyl sulfone with other aromatic diamines (such as paraphenylene diamine, 4,4'-diaminodiphenyl methane, etc.) to achieve a balance between performance requirements and manufacturing feasibility, where the composite structure provides both dyeability and cost-effectiveness

Inventive Principle:
Principle #40Composite materials

2Reliability

If 3,3'diaminodiphenyl sulfone is used at high concentrations, then the fiber achieves high dyeability and solubility, but the manufacturing cost increases

Engineering Contradiction:
ImprovedyeabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent optimizes the concentration parameter by specifying 3,3'-diaminodiphenyl sulfone at least 25 mole percent (not excessively high) of total amine monomers, which maintains adequate dyeability while controlling manufacturing costs through balanced composition

Inventive Principle:
Principle #35Parameter changes

3Temperature

If para-oriented structure is maintained for high temperature stability, then the fiber achieves flame resistance, but the complexity of monomer selection and polymerization increases

Engineering Contradiction:
Improvehigh temperature stabilityVSAvoidmonomer selection and polymerization complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent applies local quality by ensuring para-oriented linkage specifically at the sulfone-containing 3,3'-diaminodiphenyl sulfone units, which provides localized high-temperature stability and flame resistance without requiring all monomer units to have complex para-oriented structures, thus simplifying overall monomer selection

Inventive Principle:
Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The resulting fiber exhibits a limiting oxygen index of 21 or greater, ensuring it does not support flames in air, with break tenacity of at least 3 grams per denier, and is suitable for making flame-resistant yarns, fabrics, and protective garments.

Implementation Method 1

a copolymer formed from the polymerization solution derived from a plurality of amine monomers, including 3,3'-diaminodiphenyl sulfone amine monomer, and at least one acid monomer

Methodology Applied
Scientific EffectPolycondensation: Chemical Bonding

Data Source

PatentEP2181212B1Fibers comprising copolymers containing structures derived from a plurality of amine monomers including 3,3' diamino diphenyl sulfone and methods for making same
Publication Date: 2011.11.23 EI DU PONT DE NEMOURS & CO

AI summary

The invention concerns a fiber obtainable by spinning a copolymer from the polymerization solution, derived from a plurality of amine monomers, the plurality including 3,3'diaminodiphenyl sulfone amine monomer and at least one amine monomer having an aromatic group that is a para-oriented benzene ring, and at least one acid monomer; and yarns, fabrics and garments comprising this fiber, and methods of making the same. This fiber has use in heat-resistant protective apparel fabrics and garments.